By Darryl Fears
Washington Post Staff Writer
Tuesday, December 21, 2010; 10:59 PM
The killing season has begun.
Hordes of bats recently flew into abandoned mines and caves across the region for their annual winter hibernation - and more than likely, wildlife biologists said, tens of thousands won't fly back out.
A flesh-eating fungus has stalked and killed them for at least four years. More than one million bats from at least seven species are estimated to have died from a disease called white nose syndrome for the way it covers their snouts like baby powder. This year, as white nose sweeps west from Northeast states such as Virginia and Pennsylvania to Oklahoma, scientists are bracing for the worst.
"The worry is great, tremendous," said Greg Turner, an specialist in endangered mammals who works for the Pennsylvania Game Commission. Although white nose syndrome has been spotted in numerous Virginia caves, it hasn't yet had a profound impact on the beloved Virginia big-eared bat.
But the most common resident of this region, the little brown bat, is barely hanging on. And two other species - the tri-colored bat and the northern long-eared bat - are expected to become extinct.
"I'm seeing 100 percent mortality of those two species," Turner said. "We will have a 99 percent reduction of the little brown bat."
Last winter, two-thirds of Pennsylvania's more than 2,000 caves and 4,000 abandoned mines were affected by white nose syndrome, Turner said. This winter, game officials expect that "all the sites we know of will have white nose," Turner said.
Although most people might not mourn the demise of bats, perhaps because of the creatures' unearned reputation as a nocturnal bloodsucker, a major decrease in their numbers could pose a substantial ecological risk.
Each bat eats half its weight in insects every night, according to Wildlife Magazine, published by Defenders of Wildlife. They especially crave big crunchy moths that lay worm-producing eggs in corn.
Without bats, billions of bugs would go uneaten, and farmers and loggers might be forced to use more pesticides to protect trees and crops, potentially driving up the price of produce and further damaging the ecology. Homeowners might one day find more gypsy moths than usual threatening to destroy a beloved oak.
White nose syndrome was first discovered in a cave near Albany, N.Y., but it took years for scientists to identify its source. "It's not been recorded in history," said Jeremy Coleman, national white nose syndrome coordinator for the U.S. Fish and Wildlife Service.
Studies later showed that it was part of a mild-mannered genus of fungus called geomyces. The most familiar member of the genus is the fungus commonly known as "athlete's foot."
In 2009, scientists determined that a far more malevolent strain, geomyces destructans, was praying on little brown bats, big brown bats, Virginia big-eared bats, Indiana bats, eastern small-footed bats, northern long-eared bats and tri-colored bats, Coleman said.
Geomyces destructans and the American bats it targets share a preference for cold weather. When bats hibernate, their hearts beat once a minute, and their bodies cool to a temperature the fungus craves.
It is a horrible death. Scientist Gudrun Wibbelt compared their suffering to burn victims. "It makes holes in the surface of the skin" as it burrows in, said Wibbelt, a veterinary pathologist in wildlife diseases for the Leibniz Institute for Zoo and Wildlife Research in Berlin.
The same type of fungus is found on European bats, but scientists don't know why European bats survive and American bats die, Wibbelt said. Scientists also don't know how geomyces destructans found its way into caves in the Northeastern United States. One theory is that human explorers tracked it in and the bats passed it to each other.
The fungus moved along the northern Appalachian trail, a passage rife with trees, crops and gypsy moths that figure to flourish and possibly destroy food and plants even more as their main predator is diminished, Wibbelt said.
"Bats have a huge impact on pests, which is very important for forestry and agriculture," Wibbelt said. "Studies on bats in Texas showed that they reduce the need for pesticides."
Scientists don't know how to stop geomyces destructans. Last winter, the states of New York and Vermont trucked in healthy bats from Wisconsin for an experiment to determine if they were infected by their environment.
"They were put in a cave," Coleman said. "They were sealed in . . . and left there. They were infected within weeks and were dead within months."